title: Formulation development and stability studies of norfloxacin extended-release matrix tablets.
abstract: The aim of this research was to develop a new hydrophilic matrix system containing norfloxacin (NFX). Extended-release tablets are usually intended for once-a-day administration with benefits to the patient and lower discontinuation of the therapy. Formulations were developed with hydroxypropylmethylcellulose or poly(ethylene oxide) as hydrophilic polymers, with different molecular weights (MWs) and concentrations (20 and 30%). The tablets were found to be stable (6 months at 40 ± 2°C and 75 ± 5% relative humidity), and the film-coating process is recommended to avoid NFX photodegradation. The dissolution profiles demonstrated an extended-release of NFX for all developed formulations. Dissolution curves analyzed using the Korsmeyer exponential equation showed that drug release was controlled by both drug diffusion and polymer relaxation or erosion mechanisms. A more erosion controlled system was obtained for the formulations containing lower MW and amount of polymer. With the increase in both MW and amount of polymer in the formulation, the gel layer became stronger, and the dissolution was more drug-diffusion dependent. Formulations containing intermediate MW polymers or high concentration (30%) of low MW polymers demonstrated a combination of extended and complete in vitro drug release. This way, these formulations could provide an increased bioavailability in vivo.
authors.affiliation: Post Graduation Program in Pharmaceutical Sciences, Universidade Estadual do Centro Oeste (UNICENTRO), 85040-080 Guarapuava, PR, Brazil.
authors.forename: Paulo Renato
authors.initials: PR
authors.lastname: Oliveira
authors.forename: Cassiana
authors.initials: C
authors.lastname: Mendes
authors.forename: Lilian
authors.initials: L
authors.lastname: Klein
authors.forename: Maximiliano da Silva
authors.initials: Mda S
authors.lastname: Sangoi
authors.forename: Larissa Sakis
authors.initials: LS
authors.lastname: Bernardi
authors.forename: Marcos Antônio Segatto
authors.initials: MA
authors.lastname: Silva
mesh_terms: D002626:Chemistry, Pharmaceutical; D003692:Delayed-Action Preparations; D004355:Drug Stability; D065347:Hypromellose Derivatives; D008747:Methylcellulose / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D009643:Norfloxacin / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000138:chemical synthesis / Q000737:chemistry*; D013607:Tablets; D013997:Time Factors
chemical_list: D003692:Delayed-Action Preparations; D013607:Tablets; D065347:Hypromellose Derivatives; D011092:Polyethylene Glycols; D008747:Methylcellulose; D009643:Norfloxacin